KR900000145B1 - Fuel supply control device for internal combustion engine - Google Patents

Abstract

The fuel supply control device for IC engine comrises an air flow sensor (13), an intake air detector (20), a means for calculating the fuel quantity to be reguired responsive to the output from the intake air detector, a controller (22) for controlling the fuel supply quantity, and a detector for sensing the increment of air intake quentity responsive to the increase of the engine revolution. The controller is controlled by the output from the detector for sensing the increment of air intake quantity, and thus the fuel supply is increased when an increase in the air intake quantity is detected.

Description

Fuel control device of internal combustion engine

1 is a block diagram of a fuel control device according to the present invention.

2 is a block diagram showing a specific embodiment of a fuel control device of the internal combustion engine.

3 is a block diagram showing a model of an intake system of an internal combustion engine according to the present invention.

4 is a diagram showing the relationship of the intake air amount to the crank angle.

5 is a waveform diagram showing a change in the amount of intake air in an over-show of the internal combustion engine.

6, 8 and 9 show the operation of the fuel control device of the internal combustion engine according to the embodiment of the present invention.

7 is a diagram showing the relationship between the basic driving time conversion coefficient and the AFS output frequency of the fuel control device of the internal combustion engine.

FIG. 10 is a timing chart showing timings of pros in FIGS.

* Explanation of symbols for main parts of the drawings

1: Internal combustion engine 12: Throttle valve

13: air flow sensor (Karman vortex flow meter) 14: injector

15: intake pipe 17: crank angle sensor

18: water temperature sensor 20: AN detection means

21: AN calculating means 22: Control means, and the same reference numerals indicate the same or equivalent parts.

The present invention relates to a fuel control apparatus of an internal combustion engine that detects the intake air amount of the internal combustion engine by an intake air amount sensor and controls the fuel supply amount of the internal combustion engine by this detection output.

In the case of controlling the fuel of the internal combustion engine, an intake air quantity sensor (hereinafter abbreviated as AFS) is disposed upstream of the throttle valve, and the amount of intake air per intake is calculated from this information and the engine speed to control the amount of fuel supplied.

However, when the AFS is placed upstream of the throttle valve in the air intake passage and the intake air volume of the internal combustion engine is to be detected, when the throttle valve is suddenly opened, the amount of air charged in the intake passage between the throttle valve and the engine is also measured. Since the amount of air is measured above, if the fuel amount is controlled as it is, there is a defect that becomes over rich.

For this reason, conventionally, the output of the AFS, that is, the amount of air sucked into the internal combustion engine at the predetermined crank angle AN (t), the predetermined crank angle (n-1) times and the nth time, respectively, AN (n− 1) and AN (n), when the filter constant is set to K

AN (n) = K ₁ × AN (n-1) + K ₂ × XAN (t)

AN (n) is calculated by the equation and fuel control is performed using this AN (n). This was to smooth the intake air amount for each predetermined crank angle and perform proper fuel control.

However, in the conventional apparatus, since the calculation of the intake air amount is performed, calculation delay of one or more intake air occurs, and at the time of acceleration, there is a problem in that the amount of fuel is insufficient due to the presence of air in the intake pipe, which causes a delay in detection output of the intake air amount detecting means.

In addition, since the amount of fuel attached to the intake pipe varies depending on the cooling water temperature, there is a problem in that the amount of fuel supplied varies.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fuel control device for an internal combustion engine that does not run out of fuel even during acceleration.

The fuel control apparatus of the internal combustion engine according to the present invention is provided with an intake amount increase detecting means for detecting that the intake amount is increased to increase the amount of fuel supplied when the intake amount is increased, and increase or decrease the increase amount by the output of the water temperature detection means. will be.

When the internal combustion engine is accelerated, the amount of intake air increases, and accordingly, the amount of fuel supplied also needs to be increased.

Therefore, in the present invention, an increase in the amount of intake air is detected to increase the amount of fuel supplied, and the amount of fuel supplied is increased or decreased by cooling water temperature.

Embodiments of the present invention will now be described with reference to the drawings. 3 shows the intake system model of the internal combustion engine, 1 is the internal combustion engine, and if it has a volume of Vc per stroke, the Karman vortex flowmeter AFS 13, the throttle valve 12, the surge tank 11 and the intake pipe ( Air is sucked in through 15 and fuel is supplied by the injector 14.

Here, the volume from the throttle valve 12 to the internal combustion engine 1 is called Vs. 16 is an exhaust pipe.

4 shows the relationship of the intake air amount with respect to the predetermined crank angle in the internal combustion engine 1, and (a) shows the predetermined crank angle of the internal combustion engine 1 (hereinafter referred to as SGT). (b) shows the amount of air Qa passing through the AFS 13, (C) shows the amount of air Qe taken in by the internal combustion engine 1, and (d) shows the output pulse f of the AFS 13.

In addition, the operation periods of the (n-2) to (n-1) th times of the SGT are t (n-1), and the operating periods of the (n-1) to nth times are to and the periods t (n-1) and to Qa (n-1) and Qa (n), the periods to (n-1) and to the amount of air sucked by the internal combustion engine 1 in the period Qe (n-1, respectively). And Qe (n).

The average pressure and average intake temperature in the surge tank 11 during the periods t (n-1) and to are Ps (n-1), Ps (n), Ts (n-1) and Ts (n), respectively. Shall be.

Here, for example, Qa (n-1) corresponds to the number of output pulses of the AFS 13 between t (n-1). In addition, since the rate of change of the intake air temperature is small, Ts (n-1) ≒ Ts (n), and the charging efficiency of the internal combustion engine 1 is constant,

Ps (n-1) Vc = Qe (n-1) RTs (n)... (One)

Ps (n) Vc = Qe (n) R Ts (n)... (2)

It becomes Provided that R is an integer.

When the amount of air remaining in the surge tank 11 and the intake pipe 15 in the period tn is ΔQa (n),

By the formula (1)-(3)

Get

Therefore, the amount of air Qe (n) sucked into the period tn by the internal combustion engine 1 can be calculated by the equation (4) based on the amount of air Qa (n) passing through the AFS 13.

If Vc = 0.5l Vs = 2.5l

Qe (n) = 0.83 × Qe (n−1) + 0.17 × Qa (n)... (5)

It becomes

5 shows the state when the throttle valve 12 is opened. In FIG. 5, (a) is the opening degree of the throttle valve 12, (b) is the intake air quantity Qe which passes through the AFS 13, and overshoots. (c) is the air quantity Qe which the internal combustion unit 1 correct | amended by Formula (4) inhales, and (d) is the pressure P of the surge tank 11. (e) shows the change amount Qe of Qe, and (f) shows the fuel supply amount f. Where f ₁ is based on Qe and F ₂ is

Corrected based on ΔQe.

1 shows the configuration of a fuel control device of an internal combustion engine according to the present invention, where 10 is an air cleaner installed upstream of the AFS 13, and the AFS 13 is dependent on the amount of air sucked into the internal combustion engine 1. As shown in Fig. 4 (d), a pulse is outputted, and the crank angle sensor 17 is rotated as shown in Fig. 4 (a) according to the rotation of the internal combustion engine 1 (for example, at the leading edge of the pulse). 180 ° with the crank angle to the next leading edge).

20 is an AN detecting means and calculates the number of output pulses of the AFS 13 exposed between the predetermined crank angle of the internal combustion engine 1 by the output of the AFS 13 and the output of the crank angle sensor 17. 21 is an AN calculating means, which is calculated by the output of the AN detecting means 20 as shown in Eq. (5), and corresponds to the number of pulses corresponding to the output of the AFS 13 corresponding to the amount of air assumed to be sucked by the internal combustion engine 1. Calculate

Moreover, the control means 22 is the amount of air sucked into the internal combustion engine 1 by the output of the water temperature sensor 18 (for example, dummyster) which detects the cooling water temperature of the output internal combustion engine 1 of the AN calculation means 21. In response to this, the driving time of the injector 14 is controlled, and the amount of fuel supplied to the internal combustion engine is controlled in this example.

FIG. 2 shows a more specific configuration of this embodiment, where 30 is an output signal of the AFS 13, the water temperature sensor 18, and the crank angle 17 as inputs. Control device for controlling two injectors 14, the control device 30 being equivalent to the AN detecting means 20 to the control means 22 of FIG. 1 and having a ROM 41 and a RAM 42. (Hereinafter abbreviated as CPU) 40 is realized.

31 denotes an exclusive logic in which two dividers connected to the output of the AFS 13 are connected, and 32 denotes an input of the two dividers 31 as one input and the other input terminal is connected to the input P ₁ of the CPU 40. The output terminal is connected to the counter 33 and the input P ₃ of the CPU 40.

34 is an interface connected between the water temperature sensor 18 and the A / D converter 35, 36 is a waveform shaping circuit, and the output of the crank angle sensor 17 is input, and the output thereof is an interruption input P ₄ of the CPU 40. , And a counter 37.

Further 38 is a timer, 39 is an A / D converter 43 and the driver (44) CPU (40) for outputting a voltage of a battery not shown in the A / D conversion by CPU (40) connected to the interrupt input P ₅ It is a timer installed in the liver, and the output of the driver 44 is connected to the injector 14.

Next, the operation of the above configuration will be described. The output of the AFS 13 is divided by the divider 31 and input to the counter 33 through an exclusive logic gate 32 controlled by the CPU 40. The counter 33 measures the period between trailing edges of the output of the gate 32.

The CPU 40 inputs the trailing edge of the gate 32 to the interruption interruption input P ₃ and interrupts the interruption every output pulse period of the AFS 13 or every 2 minutes thereof to measure the period of the counter 33. .

The output of the water temperature sensor 18 is converted into a digital value every predetermined time by the A / D converter 35 after the voltage is converted by the interface 34 and input to the CPU 40.

The output of the crank angle sensor 17 is input to the interruption interruption input P ₄ and the counter 37 of the CPU 40 via the waveform shaping circuit 36.

The CPU 40 performs the interruption interruption processing for each leading edge of the crank angle sensor 17 to detect the period between the leading edges of the crank angle sensor 17 from the output of the counter 37. Timer 38 is transmitting the interrupt signal to the interrupt input P ₅ of the CPU (40) every predetermined time.

The A / D converter 39 performs A / D conversion of the battery voltage (not shown), and the CPU 40 inputs data of the biaxial battery voltage every predetermined time. The timer 43 is preset in the CPU 40 and is started from the output port P ₂ of the CPU 40 to output a predetermined pulse width, which outputs the injector 14 through the driver 44.

Next, the operation of the CPU 40 will be described with the procha art shown in Figs. 6 and 8-9. First, FIG. 6 shows the main program of the CPU 40. When a reset signal is input to the CPU 40, the staff 100 initializes the RAM 42, input / output ports, etc., and the water temperature sensor in the step 101. The output of (18) is A / D converted and stored in the RAM 42 as WT. At the step 102, the battery voltage is A / D converted and stored in the RAM 42 as VB.

The step 103 calculates the rotational speed Ne by calculating 30 / T _R from the period TR of the crank angle sensor 17.

AN / Ne / 30 is calculated by the load data AN and rotation speed Ne which are mentioned later by the staff 104, and the output frequency Fa of the AFS 13 is calculated.

The step 105 calculates the basic drive time conversion coefficient Kp based on f ₁ set for the output frequency Fa and Fa shown in FIG. In the step 106a, the conversion coefficient Kp is corrected by the water temperature data WT and stored in the RAM 42 as the drive time conversion coefficient K ₁ .

The staff 106b corrects the basic drive time conversion coefficient K _PA at the time of acceleration weight by the water temperature data WT and stores it in the RAM 42 as the drive time conversion coefficient K _IA .

In other words, when the water temperature is low, more fuel is attached to the intake pipe 15, so that a larger amount of fuel is required by 2 minutes. When the water temperature is high, the amount of fuel attached is small and the amount of fuel supplied is at least.

The staff 107 maps the data label f ₃ stored in the ROM 41 in advance by the battery voltage data VB, calculates a dead time, and stores the dead time in the RAM 42. After the processing of the staff 107, the processing of the staff 101 is repeated again. 8 shows the interruption interruption processing for the interruption interruption input P _3, that is, the output signal of the AFS 13.

The step 201 detects the output T _F of the counter 33 and shakes off the counter 33. This TF is the period between leading edges of the gate 32. If the division mark in the RAM 42 is set in the step 202, the step 203 divides T _F into two and stores it in the RAM 42 as the output pulse period T _A of the AFS 13.

Next, by adding the two times the remaining pulse data P _D to the accumulated pulse data P _R in the step (204) and a new cumulative pulse data P _R. The accumulated pulse data P _R adds up the number of pulses of the AFS 13 output between the leading edges of the crank angle sensor 17 and handles 156 times one pulse of the AFS 13 for the convenience of processing. When the division mark is reset in the step 202, the step 205 stores the period T _F as the output pulse period T _A in the RAM 42 and the remaining pulse data in the accumulated pulse data P _R in the T step 206. Add P _D.

The step 207 sets 156 to the remaining unfolded data P _D. If the division mark is set in the re-staff 208 if a set of T _F> 2mec, in the case of the other T _F <4msec if the staff 210 advances to step (209).

The staff 209 sets the division marker, and the staff 210 shakes off the division marker and inverts P ₁ in the staff 211. Therefore, in the case of the processing of the step 209, a signal enters the interruption interruption input P ₃ at the timing of dividing the output pulse of the AFS 13 by two, and the output of the AFS 13 when the processing of the step 210 is performed. Each interrupt is input to the interruption interruption input P ₃ .

After the staff 209 and 211 processing, the interruption interruption processing is completed. 9 shows the interruption interruption processing when the interruption interruption signal is generated at the interruption interruption input P ₄ of the CPU 40 by the output of the crank angle sensor 17.

The step 301 reads the period between the leading edges of the crank angle sensor 17 by the counter 37, stores it in the RAM 42 as the period TR, and shakes off the counter 37. When there is an output pulse of the AFS 13 in the period TR in the step 302, the time to1 of the output pulse of the AFS 13 immediately before the step 303 in the step 303 and the time of interruption of the crank angle sensor 17 at this time. If in the period T _R, and in this period Ts to calculate the time difference Δt = to2 to2-to1 not the output pulses of the AFS (13) has a period T _R with a period Ts.

The step 305 converts the time difference Δt into the output pulse data ΔP of the AFS 13 by calculating 156XTs / T _A.

That is, assuming that the output pulse period of the previous AFS 13 and the output pulse period of the current AFS 13 are the same, pulse data ΔP is calculated. In the step 306, if the pulse data? P is less than 156, the step 308 is clipped to the step 308, and the step 307 clips? P to the 156.

The step 308 subtracts the pulse data ΔP from the residual pulse data P _D to be the new residual pulse data ΔP. In the step 309, if the residual pulse data P _D is positive, the step 313a is obtained. In other cases, the pulse data ΔP is excessively larger than the output pulse of the AFS 13, so the step 310 causes the pulse data? _{As in D} , the remaining pulse data P _D is zero in the step 312.

Step (313) to the accumulated pulse data P _R pulse data ΔP ㄹreu added and a new jiksan pulse data P _R. This data P _R corresponds to the number of pulses assumed to be output by the AFS 13 between the leading edges of the crank angle sensor 17 at this time. In the staff 314, calculations corresponding to equation (5) are performed. That is, K ₁ AN + (K ₂ ) P _R is calculated by the load data AN calculated by the previous leading edge of the crank angle sensor 17 and the accumulated pulse data P _R , and the result is set as the new load data AN this time.

If the load data AN is larger than the predetermined value α, the staff 315 clips the α to the staff 316 to prevent the load data AN from becoming larger than the actual value even when the internal combustion engine 1 is deployed.

The accumulated pulse data P _R is shaken off at the staff 317. The step 318a calculates driving time data T ₁ = AN · K ₁ + T _D based on the load data AN, the driving time conversion coefficient K ₁ , and the dead time T _D.

Further staff (318b) in the seek order ΔAN with the new load data AN and the previous load data AN _O LD staff (318c) in the case ΔAN is determined whether or not larger than β ₁ small, the process proceeds to the staff (318g).

In the case of ΔAN> β ₁ , the step 318d determines whether or not ΔAN is larger than β ₂ , and if it is small, proceeds to the step 318f. If large, the step 318e clips ΔAN to β ₂ . It advances to the staff 318f.

The step 318f obtains the drive time data T ₁ from T ₁ , ΔAN and K _IA , and stores it in the RAM 42 with AL _O LD = AN at the step 318g.

Next, by setting the driving time data T ₁ to the timer 43 at the step 319 and triggering the timer 43 at the step 320, four injectors 14 are simultaneously driven according to T ₁ , and the interruption interruption processing is performed. To complete. FIG. 10 shows the timing when shaking off the dispense marks of the processes of FIGS. 6 and 8-9, (a) shows the output of the divider 31, and (b) shows the crank angle sensor 17. FIG. ) Is displayed. (c) indicates residual pulse data P _D and is set at 156 for each leading edge and trailing edge of the frequency divider 31 (leading edge of the output pulse of the AFG 13) to determine the crank angle sensor 17. For example, P _DI = P _D -156xT _S / T _A

(This corresponds to the processing of staff 305-312).

(d) shows the change of the accumulated pulse data P _R and shows the state in which the residual pulse data P _D is accumulated for each leading edge or trailing edge of the output of the divider 31.

In the above embodiment, the output pulses of the AFS 13 between the leading edges of the crank angle sensor 17 are calculated, which may be between the trailing edges, and the output pulses of the AFS 13 for several cycles of the crank angle sensor 17. You may calculate the number.

The output pulses of the AFS 13 are calculated, but the number of output pulses multiplied by an integer corresponding to the output frequency of the AFS 13 may be counted.

In addition, the use of the ignition signal of the internal combustion engine 1 other than the crank angle sensor 17 is also used to detect the crank angle.

As described above, according to the present invention, the increase in the intake amount is detected by the increase in the intake amount at the acceleration of the internal combustion engine, and accordingly the supply fuel amount is increased, and the shortage of the fuel amount due to the calculation delay of the intake amount or the delay of the control system can be corrected. In addition, the amount of fuel can be increased or decreased by cooling water temperature, so that the proper air-fuel ratio control can be performed.

Claims (3)

An airflow sensor for detecting the amount of air sucked into the internal combustion engine, a rotation sensor for generating an output corresponding to the rotation of the internal combustion engine, the detection of the intake air per one intake of the internal combustion engine based on the output of the rotation sensor and the output of the airflow sensor AN detection means, AN calculation means for calculating the required fuel amount based on the output of the AN detection means, and control means for controlling the fuel supply amount of the internal combustion engine by the output of the AN calculation means. A fuel control device for an internal combustion engine, comprising: an intake air amount increase detecting means for detecting an increase in the intake air amount; and controlling the control means by an output of the intake air increase detection means and increasing a fuel supply amount to the internal combustion engine. . An airflow sensor for detecting the amount of air sucked into the internal combustion engine, a rotation sensor generating an output corresponding to the rotation of the internal combustion engine, the intake amount per one intake of the internal combustion engine based on the output of the rotation sensor and the output of the airflow sensor AN detecting means for calculating the required fuel amount based on the output of the AN detecting means, control means for controlling the fuel supply amount to the internal combustion engine by the output of the AN calculating means, and detecting that the intake air amount is increased. And an air intake increase detection means and a water temperature detection means for detecting the cooling water temperature of the internal combustion engine, and increase the fuel supply amount by the output of the air intake amount detection means during acceleration and increase the increase amount by the output of the water temperature detection means. Fuel control device for an internal combustion engine, characterized in that. The fuel control device for an internal combustion engine according to claim 1 or 2, wherein a limit is set on an increase in the amount of the supplied fuel.

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